Hyland's also makes a homeopathic Cough Syrup w/honey, and they make a homeopathic Cold n Cough for multisymptoms like your describing. Benadryl is for allergies, and although most doctors approve it for children 2 yrs and older (for allergies) it really shouldnt be used to "help children sleep" with cold symptoms, or to stop runny noses.
They sell the Hyland's brand at Jewel/Osco. It was recommended to me and has been in business since 1903, so we trust it.
Good luck! I know it is so hard to watch your little one's be sick.